


Three's a Crowd

by chromyrose



Category: Haikyuu!!
Genre: Bisexuality, F/M, Jealousy, M/M, Polyamory, Threesome - F/M/M
Language: English
Status: Completed
Published: 2015-12-08
Updated: 2015-12-08
Packaged: 2018-05-05 13:50:53
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,079
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5377586
Author URL: https://archiveofourown.org/users/chromyrose/pseuds/chromyrose
Summary: <blockquote class="userstuff">
              <p>Hinata and Yachi start dating. Kageyama can't tell who he's more jealous of.</p>
            </blockquote>





	Three's a Crowd

**Author's Note:**

> Another fill I did for the hqkinkmeme over on dreamwidth, but this fic refused to go to a smutty place so it's perfectly SFW (and pretty adorable, in my biased opinion). Request was as follows: 
> 
> "i want something with these three getting together in a closed poly relationship, with lots of communication and kindness (even from kageyama) 
> 
> bonus points if it's not kagehina who gets together first  
> bonus bonus points if it involves non-penetrative sex"

The first morning Hinata comes in late to practice, with his cheeks ruddy and his fingers twined with Yachi's, all Kageyama can wonder is when exactly those two found the time to get together. Morning practice starts a few hours before their first classes, and they keep training into the evening, continuing on most days until well after the sun sets. Lunchtime would make sense as an option if Kageyama himself wasn't always there, resisting the urge to gnaw on his pencil in frustration while Yachi patiently explained English verb conjugations for a fifth time. 

Tanaka and Nishinoya's rowdy hollering sounds so much farther away than it should, probably because there's a beating in Kageyama's ears that's so, so loud. He can't tell if it's from his heart or the ball he's dribbling hard into the court as he tries to shake off the sudden, inexplicable tension in his shoulders. He's waiting for Daichi or Sugawara to interrupt the huddle that's growing around his friends, but Suga's clear laugh rings through the gym, and even Daichi is smiling when Kageyama looks up again. Hinata is hard to see in the middle of bigger, taller teammates, but what's visible of his face clashes terribly against his orange hair with how red it is. Yachi doesn't seem to be faring any better, if the incomprehensible stammering is anything to go by. 

Kiyoko is Kageyama's savior, in the end; she produces a whistle from her bag and blows loud enough that pretty much everyone claps their hands to their ears and winces. Then, with an innocent, angelic voice, she reminds them, “You should warm up before Coach Ukai comes in.” 

After that Daichi retakes his strict posture, and barks out orders for laps around the gym. The second years groan, but follow after Tsukishima, the first person to take off running. Kageyama joins the mob as well, musing as he runs as to why it bothers him so much, that Hinata and Yachi are holding hands now, coming to school together. Did he let her ride on the back of his bike? Their houses aren't in the same direction, but Hinata usually leaves much earlier than he has to, so maybe he went over to meet her first... 

Thinking on the subject feels like poking at a bruise on his brain, so Kageyama huffs and decides that if he has energy to expend thinking about stupid things, he should be running harder.

–

Morning practice starts off poorly, with Hinata missing nearly every toss he's given. His eyes are darting to the sidelines way too often, but with a sharp tone and a few choice words Kageyama is able to reign his focus back in on the court, and things go more smoothly. After that he keeps to himself, during cool-downs and in the locker room, and as lunch approaches Kageyama feels like something is boiling in the pit of his stomach. His feet don't want to move but he picks them up anyways and heads to Yachi's classroom, and is surprised (and relieved, and surprised by his relief) that Hinata isn't there yet. 

“He sort of, um, insisted that he had to get me a juice from the machine downstairs?” Yachi explained, waving her hands anxiously in the air between them. “I tried to tell him I don't need anything, but you know how stubborn Hinata can be...” 

Kageyama knows, and in his mind's eye he can see that glassy look that Hinata gets in his eyes when he's decided he's not going to budge. A shiver moves down his spine before he can stop it, and he hides it flipping open his notebook. 

“Okay,” he says, grappling with himself to suppress the growing list of questions inside of him that feels like a coiling spring ready to burst at any moment. “So for the homework from last night, how are you supposed to fill this in?” 

Yachi seems to breathe more easily after that, as she moves her chair in closer to look over his notebook, but the smell of her shampoo filling his senses only makes Kageyama's stress levels rise. 

– 

In the end, Kageyama doesn't have to ask for a single detail: Hinata volunteers the entire story after practice, while they're walking together as they always have until their paths home diverge. Yachi had to stay behind to plan fundraising events with Kiyoko, Daichi, Suga, and Tadeka-sensei, but insisted that they go on ahead, really.

“-so then she was telling me about this big project her Mom is working on, and how she was coming home close to midnight, and I guess my mom heard me repeat that part and said we had to invite Yachi for dinner so she wouldn't have to eat convenience-store bentos every night. And then we went to my room to study but we had to leave the door open, because, um, you know-” even though the sun had dipped below the horizon, there was still enough light to see that Hinata's ears were red. “-Yeah, you know. But Natsu kept coming in and singing that little kids' song about sitting in trees, and it made Yachi really embarrassed and nervous! And I guess I thought maybe if I kissed her it would prove that there's nothing wrong with kissing- and I know that sounds like a really stupid idea when I say it now but it all worked out!” 

Kageyama hums to prove that he's listened, and because Hinata has a point: they're an official couple now, whatever that means for first years in high school. He doubts he'll ever find out, since he doesn't intend on dating anyone, and he'll probably kill Hinata if he tries to tell him. 

Hinata also has a point when he says it's a stupid idea, and Kageyama is kind of pissed that something like that even worked. Yachi is... more special than that- no. Kageyama cuts off that train of thought before it can depart from the station and cause any damage. 

“Congrats,” he huffs finally, kicking up a little dirt when he drags his feet as they walk. “But if this means you're going to be distracted every time we're on the court now--” 

“It doesn't!” Hinata promised quickly, removing a hand from the handlebar of his bike to put it up like he's pleading, or taking an oath. 

“Good,” Kageyama says. Before he can help himself, the rest of the sentence comes out, “because I'm your partner when we play.” 

Hinata sort of sucks in a loud breath and Kageyama can't really decipher what it's supposed to mean. He realizes he's probably overstepped a boundary now, even though that kind of talk isn't new for them, but it feels weird to acknowledge that their partnership on the court somehow rivals a romantic one. Kageyama's gut is really upset with him after that, and while Hinata's silence doesn't make it any better, at least he's doesn't say anything that makes it any worse. 

When they finally reach the part of their trips where Hinata has to turn for the mountains, he kicks off and hops right onto his bike with the same vigor he uses every other day. He turns back around to face Kageyama and grins. 

“See you tomorrow morning, partner!” 

By the time Kageyama's jaw is in working order again, he only manages to mutter, “Watch where you're going, dumbass.” By then, Hinata is already too far away to hear him. 

–

Because Hinata is still Hinata even when he's managed to get himself a girlfriend, there are four instances over the next three weeks where he begs Kageyama for spare change for the vending machine because he's left his coin purse in his other pocket. The first time it happens, Kageyama scolds him, “It's stupid to make another guy pay for a gift for your girlfriend!” After that, he hands the coins over without a word and pretty much hates himself for being weak to Hinata's pleading eyes. 

Contrary to what Tsukishima might say, Kageyama isn't outright stupid, though he is slow when it comes to understanding emotions. His dreams are a big help in deciphering all the gross feelings coming out of his guts; a guy can only close his eyes and find the image of warm, fiery, gentle, molten brown eyes there so many times before the implications set in. Hinata and Yachi... are cute. Individually on one level, but when they're standing together, Hinata sheepishly rubbing the nape of his neck and Yachi awkwardly patting his shoulder, it's an entirely different sort of cute. It's like they're a present, and he wants to put his arms around them both, pull them in to his chest.

The real issue there is the “both.” He's noticed guys as well as girls in the past, even if he hasn't noticed himself noticing them until it was only in hindsight, but liking two people at once sort of makes him hate himself. It brings to mind the image of a greedy King. 

“-geyama? Oi, Kageyama! Are you even listening to me, idiot?” 

“Huh?” He answers inelegantly, suddenly becoming aware of his surroundings again. They're having lunch outside, because there aren't any exams to study for this week and Hinata begged for a break and fresh air. Once he turned those eyes on Yachi she lost all her nerve to argue, though in this particular instance Kageyama finds he can't blame her. 

“I was asking if you saw the volleyball special that was on the sports channel last night!” Hinata recaps impatiently, with a really distracting grain of rice stuck on the corner of his lip. “I really wanted to but Natsu was hogging the TV for one of her movies.” 

Kageyama suddenly remembers the advertisments on TV and the talk amongst the guys in the club room about the documentary film, and clicks his tongue. 

“I forgot about it,” he replies vaguely, turning back to his food so as to suppress the urge to clean Hinata's face. 

“ _You_ forgot about it?” Hinata gasps, but he was obviously also laughing. “What else could even have been on your mind other than volleyball?” 

“Stuff.” 

“What, you're not even going to tell us? Boo!” 

“Hinata, he doesn't have to tell us anything,” Yachi cuts in nervously, probably sensing some sort of conflict. Kageyama wonders, not for the first time, if Hinata ever pushes her buttons too, or if Kageyama is just special that way. 

“And I thought that you guys might miss it,” she adds quickly. “Or that someone else on the team might, if they were studying or something... So I recorded it.” 

Lacking a better word for it, Kageyama categorizes the noise Hinata makes as a squeal. 

“You really are an angel!” He praises immediately, taking one of Yachi's hands in his two. “Never doubt your manager skills! Or your girlfriend skills!” 

“E-eh?” 

“Promise me? Because you're the absolute best.” 

Kageyama grabs his chopsticks to poke around at his lunch so that he doesn't have to watch misty-eyed Hinata shake Yachi's arm. He wishes that Yamaguchi didn't always eat lunch with Tsukishima, because he might have made better lunch company than the two lovebirds. 

“I-I promise!” Yachi exclaims, and Kageyama gets the sense it's more to make Hinata stop before he dislocates her shoulder. “I was just going to say, if it's okay with Kageyama-kun, you both could come over after practice and we can watch it together?” 

Hinata turns his pleading gaze on Kageyama and it makes his heart jump in his chest; fortunately he'd already planned to say 'yes,' because he sort of forgot what his other options were. 

“If it's no trouble, Yachi-san,” he manages a polite reply, nodding and picking up his milk carton. He sucks it all down in one desperate gulp, to give himself an excuse to shut his eyes and shut everything out. 

– 

The documentary is about the history of Olympic volleyball, and it's incredible. Lots of clips from some of the most iconic plays are included, and though Kageyama has already seen the majority of them, it's different watching it on a large TV screen, some of them remastered from the old VHS quality, than it was seeing them in the tiny Youtube player. He's so engrossed in the video that it's easy to forget he's on Yachi's living room couch, with the length of Hinata's arm pressed to his own. They showered after practice but Hinata still manages to smell a little like sweat under the clean soap, like he maybe wasn't as thorough as he could've been. That smell is the thing that feeds the nagging voice in the back of his head, _'Just stretch your arm around them. You can probably reach Yachi's shoulder easily, they're both so small--'_

There is a lull in the documentary, where people in suits are talking to the camera about how rules have changed over the ages, and it's not being supplemented by clips of anything. Yachi excuses herself to go make more popcorn, and Kageyama can't say he blames her for finding it boring; that said, it is kind of annoying when Hinata starts poking him. 

“You need to pay attention, idiot!” He scolds. “You probably don't know any of this and you're actually on the court!” 

That's enough to get Hinata to leave him alone, and he can see in his periphery the way Hinata crosses his arms over his chest and huffs. It shouldn't be adorable to see him sulk like a petulant child, so that kind of makes Kageyama hate himself, but he just forces his attentions to refocus. 

When Yachi comes back, she has a bowl of popcorn in her hands, and surprises Kageyama by sitting down on the other side of him instead of beside Hinata again. Now he's the one in the middle, and he's hoping no one hears the little squeak that comes out of him. 

Yachi smells really, really good: something like flowers and warmth. That's something she has in common with Hinata, the warm smell; he's pretty sure no one can say that about him. It's like their personality manifesting itself into something you can sense physically, something way too endearing. His heart starts beating uncomfortably in his chest as he attempts to get comfortable while not letting his arms touch either of them. 

A few minutes later Hinata leaps off of the couch suddenly, with a squealed, “Bathroom,” before he's running down the hall. Kageyama makes a repulsed face, because _gross_. Yachi reaches for the remote and pauses the program. There is silence between them for a long moment, filled by the really loud ticking of the kitchen clock's second hand. And then Yachi sort of clears her throat and leans forward so she can look at his face. 

“I don't mean to be presumptuous, Kageyama-kun, but um... I guess I noticed that you've seemed really far away since Hinata-kun and I started dating...” 

“I'm not far away,” he replies quickly, trying to keep his face neutral. Kageyama wonders why she's noticed anything he's done, or if maybe he's just completely obvious. He tries not to give anything away in this conversation, but he isn't sure what is or isn't the right way to act at all. “I've been right here. Training. Studying.” 

“I know!” Yachi is quick to add, like she's worried he's offended. He's not offended, actually, just guilty that he's so pleased that she's noticed him. “I just... I thought maybe you were feeling left out. Do you like Hinata-kun?” 

Kageyama quite literally chokes on his next breath. Yachi screams and starts thumping him on the back, but her strikes are so delicate they really wouldn't be of any help even if he was choking on something tangible. Even when he recatches his breath, Kageyama won't answer, and he doesn't meet her gaze. He hopes she will naively believe his cheeks are only red because of his breathlessness, but Yachi is the smart one so the odds of that are zero to none. 

“I kind of thought so. I'm sorry, Kageyama-kun...” 

“D-don't. Don't be sorry,” he huffs. 

Yachi shrugs, pulls her arms a little more tightly around herself. “I'm _so_ sorry,” she says firmly. “Because... this is even more presumptuous. Do you... l-like me?”

Kageyama knows the second years do animal dissections in science class. He wonders distantly if this is what the frog feels like splayed open on the table. He is now removed from the situation, ascended to another plane, or more like descended, down to the deepest pits of Hell. He's living a nightmare. If he was more like Hinata or Yachi, he'd have tears in his eyes, but he's too emotionally reticent to do anything but gape. 

Yachi getting closer is something he's probably hallucinating, Kageyama thinks, until her hand falls on his shoulder and the heat from her face is radiating onto his chin. You can't hallucinate sensations, can you? 

Yachi kisses his lips; Kageyama is a teenaged boy so he knows that the simple touch of two sets of lips is incredibly tame for a kiss, but when it's your (arguably) best friend's girlfriend doing it to you, it might as well be full-on, with tongue. Her mouth is soft and warm, and there's kind of a cherry smell involved, and Kageyama mentally catalogues all of this in spite of himself before he pushes her off. 

“You're dating Hinata!” He hisses painfully. Yachi's cheeks are bright red, and she's waving her arms wildly; all-in-all, she looks like some air-traffic controller. 

“I-It was his idea!” She wailed. “He was the one who thought you might feel left out! But we thought maybe if he was the one who asked you, you'd think I was just going along with it for your sake! He's not even really in the bathroom right now!” 

“Yacchan!” Hinata whines from the hallway, poking his head back into the room. “There's no point to making a secret plan if you're just going to tell the target about it! Besides, you were the one who wanted to kiss him first.” 

Yachi is moving her mouth and making noises, but they aren't comprehensible words. Hinata comes over and gets on his knees on the ground between them, looking up at Kageyama hopefully. Kageyama isn't sure _what_ he feels. 

“Just. What. What is going on?” He manages finally. Words are so hard right now, between his own hope that he's not misunderstanding and the voice reminding him that he probably is, and getting his hopes up will _destroy_ him. 

“Bakageyama,” Hinata scoffs pleasantly. “We want you to be our boyfriend!” 

Kageyama feels his face crumple and he buries it deep in his hands from the shame. 

“Are you _crying_ , you big stupid baby?” Hinata laughs, high and clear, as Yachi starts to squeak and pet his hair. His face is pulled out his hands and into her thigh, and fortunately Yachi tells Hinata off of teasing him. Kageyama doesn't move until he feels like his face is dry and normal again, and Hinata's grin is pulled from ear to ear as he reaches for Kageyama's cheeks and pulls him into a deep, deep kiss. 

–

The first two weeks are a terrible adjustment period for Kageyama. It's hard to go from being a single loner to being in a relationship, and doubly so when there are two tempos to learn. Yachi seems to struggle a little too, and if Kageyama had to guess, he would say her biggest concern is treating them equally. 

Unsurprisingly, Hinata takes to this new relationship with apparent ease. He can go from putting cute braids in Yachi's hair to petting Kageyama's arm without difficulty, while Kageyama has to assure himself over and over again, ' _this is okay_ '. 

They typically go to Yachi's house with whatever free time they have, because they are teenagers and they are dating, and the idea of having a place free of adults (or really anyone else at all) where they can be together is too appealing to deny. It works out well because Hinata and Kageyama both get their homework done faster and better when they can ask for help from someone who knows what she's doing, and then they have the rest of their evenings to learn how to be in their space. 

On this particular night, Hinata seems riled up, and he's taking Kageyama there with him.

“I bet I'm a much better kisser than you,” he says haughtily. “When we kiss I can feel how stiff your jaw is and it's totally freaky!” 

“At least I'm not slobbering on the person I'm kissing,” Kageyama huffs. “I don't want to be kissing a dog, and I bet Yachi-san doesn't either.” 

“That's it!” Hinata declares. “I bet Yacchan can tell us who the better kisser is.”

Kageyama swiftly turns to Yachi, who is predictably red and stammering. 

“I couldn't pick!” She squeals. “And it's not fair to make me, either!” 

“She's right,” Kageyama cuts in, deciding to spare her before Hinata makes things worse. “She can't grade us on our performance in the past. Especially since you've had more time with her to get things right.” 

Hinata frowns and looks put-out, until Kageyama adds, “So we just have to do our best right now. Whoever makes Yachi feel the best, wins.” 

“W-what?!” She stammers, but it isn't enough to deter either of them. Kageyama wants this, wants to prove that adding him to the relationship was the right thing for Hinata and Yachi to do, that he can make her just as happy as Hinata does, or happier, even. And from the burning shine in Hinata's eyes, he wants the same thing.

“Don't worry, Yacchan,” Hinata coos, after he shakes the fever out of his expression. Now he looks innocent, excited, and more like a firecracker than a forest fire. He put his hands on Yachi's shoulders, and one of his thumbs is making little circles over her shirt. “We'll take good care of you.”

He kisses Yachi tenderly, though because it's Hinata, it's only tender for a few seconds before he's taking more. Kageyama breathes out a little chuckle and comes up behind Yachi. He's nervous, but having this be a competition makes it easier, somehow. The goal is plain, and all he has to do is strive for it. 

So Kageyama rests his hands on Yachi's waist, not at all firmly, and he leans in to kiss the bit of skin where her neck glides into her shoulder. She shuddered beneath his hands, but maybe that's because Hinata's using tongue now. Kageyama hates himself for the flare of jealousy that image provokes, and for the arousal, too. 

Hinata is moaning loudly, now, like this is about him, but it's incredibly endearing. Kageyama thinks Yachi might agree, because she's quavering. When they part to breathe, Kageyama seizes his chance to swallow those shakes, the little pants coming from Yachi's lips, and he kisses her softly. He's shy about kissing, especially with Yachi; she's all soft supple skin and he's calloused and dry and rough. But she turns so they're chest to chest, puts her hand on his shoulder, and kisses back.

Then there's the sound of a camera shutter; when they look up, Yachi red in the face and Kageyama steaming for other reasons, Hinata has the most sheepish grin on, and he's rubbing the back of his neck awkwardly. The offending cell phone is still hanging loose in his other hand.

“Oops?” He manages. “I thought it was on silent!” 

“Don't take pictures of us kissing, you idiot!” 

“But you two looked so cute,” Hinata whines. “Please keep kissing. I promise, no more pictures.”

Kageyama huffs, not quite believing Hinata's word, but Yachi looks back up at him and his brain's capacity for annoyance fizzles out. 

“I think just for that, Kageyama wins,” Yachi decides, smiling up at him. 

“E-eh?!” Hinata protests weakly. “That had nothing to do with making you feel good.” 

Without looking away from Kageyama, Yachi shakes her head. “Kageyama makes me feel safe. Hinata makes me feel treasured. Both of you make me feel adored. It's not fair to make me pick. That was the whole point of... this.” 

Kageyama and Hinata share a look; Hinata's cheeks are glowing pink, and Kageyama's pretty sure the heat in his face means he looks the same. 

“Yeah,” Kageyama agrees when he finds his voice. “Yeah.”

**Author's Note:**

> the haikyuu!! series has got me writing fic like I haven't in years. I post a lot of fic memes on my tumblr, @zahhaked, so visit me over there so you can send me requests that might turn into something rad.


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